Bravery Island is in the North Hyrule Sky Archipelago and is home to Simosiwak Shrine.

How to Reach Bravery Island
You can float to the lowest part of Bravery Island if you first go to Mayam Island and float from there to the Flux Construct's arena. From there, you can float to the lowest part of Bravery Island.
Features of Bravery Island
Talk to the Steward Construct on Bravery Island and perform the untimed test run of the Dive Ceremony. When you complete it successfully, Simosiwak Shrine will appear on the island.
Complete the timed version of the Dive Ceremony within the time limit to receive the Glide Tights.